Process of conditioning cellulose ester filaments



Patented Feb. 8, 1949 UNITED STATES PATENT OFFICE PROCESS OFCONDITIONING CELLULOSE ESTER FILAMENTS John B. Eisen, Springfield, Pa.,assignor to American Viscose Corporation, Wilmington, Del., a

corporation of Delaware No Drawing. Application November 10, 1944,Serial No. 562,903

' 3 Claims.

' as cellulose esters or ethers including cellulose acetate, ethylcellulose, cellulose aceto-propionate and cellulose aceto-butyrate, andis a continuation in part of my earlier application Serial No. 470,-664, filed December 30, 1942, now abandoned.

The application of conditioning agents to artificia'l textile materialsof the nature specified above is a common expedient to prepare the materials for textile processing operations or to impart a desired hand"in the final product. For example, the conditioning agents may beapplied to soften and lubricate textile staple fibers to facilitatetheir conversion by such processes as carding, picking, opening, andspinning into an intermediate product known as spun rayon yarns. Suchyarns may then be converted by weaving, knitting, braiding or relatedprocesses into a final fabric. Alternatively, the conditioning agentsmay be applied to continuous filamentary yarns of the organic derivativeof cellulose to facilitate their conversion into textile fabrics. Again,fabrics themselves after their formation by weaving, knitting, and thelike may be treated with the conditioning agent to impart an improvedsoftness of hand thereto.

However, in the manufacture of cellulose acetate continuous filamentyarns by the dry-spinning process, it is necessary to apply suchconditioning materials shortly after the formation of the filaments butbefore their first collection, which is generally accomplished by someform of twisting device, such as a cap or ring twister. The point ofapplication to the travelling untwisted bundle of filaments may bewithin the spinning cell between the spinneret andthe first guide, or itmay be along the course of the bundle between this guide and the drawroll or godet where the bundle undergoes a certain amount of stretchingdue to the high speed of the draw roll. A number of exacting conditionsmust be fulfilled in order that a conditioning material can be usedsatisfactorily in this situation. First of all, it must be capable ofrendering the filaments soft as contrasted with harsh. Secondly, it mustlubricate the funents. It must be present on the finished yarnexclusively in the form of a substantially continuous liquid phaseregardless of the number of ingredients of which it may be composed evenin the presence of any residual spinning solvent contained in the yarnat the time of application, and it must remain in the liquid conditionthroughout any period of storage under all temperatures from about 0 C.to 25 C. and higher. Otherwise, the yarn develops too much friction andstatic to be collected satisfactorily on modern high speed windingand/or twisting equipment. It must not require any substantial amount-ofwater or volatile solvents to render it a homogeneous liquid under theseordinary room temperature conditions even though it may comprise severalingredients; otherwise the yarn becomes overstretched and has abnormallylow extensibility, or it becomes impossible to spin the filaments atall, especially when operating at high delivery speeds. Still furtherthe conditioning material should reduce the tendency of the filaments tobuild up electrostatic charges by rubbing action upon guides and otherrelatively moved parts during textile fabrication, such as weaving andthe like.

It is extremely rare that all of these capabilities can be foundsufficiently pronounced in a single substance, and it is difiicult tofind two or more different substances which can be compatibly blended,whose capacities can complement each other to attain all the qualitiesneeded in a conditioning material enumerated above.

It has now been discovered that an entirely. new class of compounds notheretofore used for this purpose has the ability to soften and lubricateorganic derivatives of cellulose, which may be at the time ofapplication in the form of fibers, continuous filaments, spun orcontinuous filament yarns (and especially freshly formed yarns duringdry spinning) or textile fabrics, and

that their use as conditioning agents is character-' ized by. markedincidental advantages not commonly found associated together with anyparticular group of compounds. This group of compounds may be generallydesignated as the inner ethers or inner anhydrides of hexitols which arepartially esterified with a higher fatty acid of at least 8 carbon atomsand the derivatives of such partial esters obtained therefrom bycondensing them with ethylene oxide. The partial esters of the innerethers or anhydrides of such hexitols as mannitol, sorbitol, iditol, anddulcitol from such acids as stearic, oleic, ricinoleic, palmitic,myristic, lauric, or from mixed fatty acids, such as are obtainable fromfish oils, vegetable oils, or animal fats which may or may not behydrogenated, are applicable. Preferably, such partial esters alsocontain ethylene oxide residues obtained by the reaction of the partialester of the inner ether with ethylene oxide or by the 3 I condensationof the inner ether with ethylene oxide prior to esterification. Thecontent of the ethylene oxide may vary within wide limits from one totwenty or more ethylene oxide units per molecule of the inner ether orof the partial ester thereof. Depending upon the properties desired forthe particular application of the conditioning agent, the control overthe content of ethylene oxide units in the molecule can serve to balancethe content of fatty acid radicals with a hydrophilic content to anydesired point. In general, the greater the ethylene oxide content, theless tendency there is for the development of electrostatic charges onthe treated yarns. However, the introduction of too great a number ofethylene oxide units in the molecule tends to decrease the lubricity sothat it is preferable to make a compromise to obtain the optimumresults. For example, a compound containing a large proportion of fattyacid radicals, such as sorbitan trioleate, may contain a, relativelylarge proportion of ethylene oxide units in the molecule (e. g. twenty)to balance the hydrophobic, character of the three oleyl radicals foradapting the compound to use as. a conditioning agent, and thisrelationship is also advantageous when it is desired to obtain rapid andcomplete removal of the conditioning agent subsequent to the textileprocessing operation for which it is applied. On the other hand acompound such as sorbitan mono-oleatewhen applied for the same servicewould need relatively few ethylene oxide units (two or three) or none toproduce the optimum of softening, lubricity and antistatic qualities andto assure its rapid and complete removal subsequentiy.

These compounds in the form of their technical grades available on themarket vary from' liquid to pasty wax-like masses, depending mainly uponthe degree of saturation of the fatty acid chains and to some extentupon the length of such chains. For example, the unsaturated esters,such as the oleates, are liquids while the palmitates, myristates,stearates, and laurates are pasty wax-like masses. Those that areliquids can be applied directly as such without compounding. However,the others have the capability of being readily dispersed innon-volatile liquid media, such as mineral oil, to form a substantiallycontinuous liquid phase ofexcellent stability at ordinary roomtemperatures of about 15 to 25 C. encountered during storage as well asat the higher temperatures (e. g. up to about 45 C.) normallyencountered in dry-spinning rooms in which such conditioning materialsare frequently applied. The fact that the compounds are themselvesliquids or form in mineral oil liquid conditioning media facilitatestheir application at normal room temperature and especially assures highfluid consistencies at spinning room temperature. It has been found thatthe conditioning media exhibit a high degree of mono-oleates,

ter apparently accounts for the high degree of lubricity of the textilematerials treated therewith. In addition, in spite of the pronouncedhydrophobic portion of the compound, their hydrophilic nature issufiicient to assure efllcient removal with mild scouring agents whereit is desired to remove the conditioning agents or media after textileprocessing. On the other hand, if the compounds are permitted to remainupon the yarn after textile processing or fabrication procedures, theirhydrophilic content is sufficiently manifest to permit effective anduniform dyeing of the textile materials by the customary dyeingprocedures without interference therewith.

While these compounds have been found to exert a marked softening actionupon textile materials of organic derivatives of cellulose, suchsoftening action is not accompanied by any detrimental eifect upon thetensile strength of the yarns or other textile material. For thisreason, it is not thought likely that the compounds penetrate theorganic derivative of cellulose mass in the manner of a plasticizerwhich tends to dissolve or be dissolved in the mass. Instead, thecompounds are probably oriented or adsorbed on the surface of themasses, perhaps by residual valence forces. While their softening actionis probably related to the hydrophilic portions of the molecules, yetthe hydrophilic content of the compound does not appear to be sufilcientto make them definitely hygroscopic. For this reason, the softeningaction is not appreciably afiected by changes of humidity in theatmosphere and is independent of the method of application, that is,whether applied in the presence of aqueous or non-aqueous solventswhether volatile or non-volatile.

Examples of the compounds which are specified merely for the purpose ofillustration are as follows:

Sorbitan or mannitan mono-, di-, and tri-oleates, monoricinoleates,stearates, palmitates, laurates, myristates, and sorbide or mannidestearates, palmitates, laurates, myristates which may contain from zeroto twenty or more mols of ethylene oxide condensed per molecule ofester.

These compounds, whether they contain or do not contain the ethyleneoxide groups condensed therein, may be applied either from aqueous(except during dry-spinning) or non-aqueous media as they are readilyemulsifiable in aqueous media and readily dispersiblein non-aqueousmedia, such as mineral oil or volatile solvents. Such as these compoundsas are liquids at ordinary room temperature may be applied directlywithout dilution or dispersion in other media, especially to freshlydry-spun filaments. Because of their solubility and dispersibility insuch non-volatile liquid media as mineral oil, which itself can beapplied in conjunction with the conditioning agent toincrease-thelubricity, all of these compounds may advantageously be applied inconjunction with such auxiliary agents, thereby eliminating thenecessity to .use expensive volatile solvents which would not keep theconditioning medium in permanent liquid condition and at the same timemay tend to attack the textile materials of the organic derivatives ofcellulose. As stated hereinbefore, this is also an important advantagein that it makes it possible to apply a substantially permanentlyblended liquid medium during dry spinning without overstretching ordiillculties with breakage. The application of such conditioning agentsas a liquid or as a dispersion, solution, or emulsion readily lendsitself to the uniform distribution of small amounts of the conditioningagents which 'may be as low as 0.1 to 5% based on the weight of theyarn, this low proportion being adequate for most purposes to soften andlubricate the yarns, fibers, or other textile materials, particularlyfreshly spun continuous filament yarns, and render them capable of beingcollected, amenable to subsequent processing operations or, instead,

- to impart the desired softness of hand to a finish- As an illustrativeexample, a freshly spun continuous filament yarn of cellulose acetatewas passed in advance of its first collection over a coating rolldipping in a trough containing a solution in white mineral oil of 5% ofmannitan mono-oleate containing three units of ethylene oxide condensedper molecule of the mannitan mono-oleate. The yarn thus treated wasrendered soft, pliant and slippery and was collected withoutoverstretching and breakage.

Example 2 Sorbitan mono-oleate condensed with 5 mols of ethylene oxideper mol of the ester was applied in liquid form to a freshly spuncontinuous filament yarn of cellulose acetate by means of an applicatorroll in advance of its first collection preparatory to textileprocessing.

Example 3 A solution in white mineral oil of 7% sorbitan di-oleatecontaining 3 mols of ethylene oxide per molecule was applied to arunning yarn of fresh- 1y spun continuous cellulose acetate filaments bya coating roll in advance of its first collection. The

yarn thus conditioned was characterized by a soft hand, was pliant andslippe y. and its textile processing qualities were of an excellentcharacter.

Example 4 A solution in white mineral oil of 20% sorbitan di-oleatecontaining 8 mols of ethylene oxide per mol of the di-oleate and 2% of ahigher fatty alcohol sulfate was applied by spraying to celluloseacetate staple fibers. The softened and lubricated fibers were then spunby the usual processes into a spun acetate yarn.

Example 5 A solution in white mineral oil of 5% of mannitan dilaurateand 2% of a higher fatty alcohol sulfate was applied while at spinningroom temperature to a freshly dry-spun bundle of continuous celluloseacetate filaments as they proceeded from the spinning cell to a drawroll.

While preferred embodiments of the invention have been described, thedescription is intended to be illustrative only, and it is to beunderstood that changes and variations may be made without departingfrom the spirit or scope of the invention as defined by the appendedclaims.

I claim: 1

1. The process of conditioning freshly dry spun continuous filamentscontaining a cellulose organic ester which comprises applying thereto inadvance of their first collection, at a room temperature between about15 C. to about 45 0., a non-volatile, non-aqueous conditioning mediumwhich is liquid throughout said range of room temperature, comprising asolution in a mineral oil vehicle of about 5 to 20% of an ethylene oxidecondensation product of a partial higher fatty acldester of an innerether of a hexltol and a higher fatty alcohol sulfate in a relativelysmall proportion compared to the vehicle for imparting antistaticproperties to the filaments, and thereafter collecting the filaments bywinding.

2. The process of claim 1 in which the partial ester is derived fromoleic acid.

3. The process of claim 2 in which the filaments are of celluloseacetate and the collection is accompanied by twisting.

' JOHN B. EISEN REFERENCES CITED The following references are of recordin the I file of this patent:

UNI'IED STATES PATENTS Number Name Date 1,959,930 Schmidt et a1, May 22,1934 1,970,578 Schoeller et al. Aug. 21, 1934 2,150,570 whitehead Mar.14, 1939 2,297,135 Davis et al. Sept. 29, 1942 2,418,752 Brown Apr. 8,1947

